Hypoglycemic and hypocholesterolemic activities in vivo of polyphenols – popular components of dietary supplements

Polyphenols such as rutin (RUT), quercetin (KVC) and tras-cinnamic acid (TKR-k) are sought-after components of dietary supplements and functional foods for the prevention of metabolic diseases due to their bioactivity. Studies devoted to the evaluation of the complex effect of mixtures of these polyphenols are very few. The aim of this research was to evaluate mixtures consisting of different amounts of RUT, KVC and TKR-k isolated from plant cells in vitro, to exhibit hypoglycemic and hypocholesterolemic potential in vivo. The objects of the study were mixtures of bioactive compounds (mixture No. 1 - RUT : KVC : TKR-k in a weight ratio of 1:1:1; mixture No. 2 - in a weight ratio of 2:1:1; mixture No. 3 - in a weight ratio of 1:2:1; mixture No. 4 - in a weight ratio of 1:1:2). To determine hypoglycemic activity, Wistar rats weighing 250±15 g were used as a model organism. After 12 hours of fasting, they were orally administered a mixture of bioactive compounds (100 mg/kg body weight), and then, 1 hour later, they were orally given glucose at a dose of 2000 mg/kg. Then, after 30 min, 1, 1.5, 2, 4 and 6 hours, blood plasma glucose and total cholesterol (TC) levels were estimated. To determine hypocholesterolemic activity, C57Bl/6 mice were used, which were orally administered a mixture of bioactive compounds (100 mg/kg body weight) daily for 14 days, and hypocholesterolemia was created using poloxamer P407 (three times a week intraperitoneally at a dose of 400 mg/kg). At the end of the experiment, blood plasma levels of glucose, TC, low-density lipoproteins (LDL) and triglycerides were estimated. In the hypoglycemic load experiment, mixture No. 3 reduced blood glucose level (р<0.05). In the hypocholesterolemic load experiment, all mixtures reduced blood glucose levels (р<0.10). Only mixture No. 4 caused a reliable decrease in the level of TC (2 fold lower compared to the control group, р<0.01) and LDL (1.72 times lower compared to the control group, р<0.10). The relationship between the ratio of bioactive compounds in mixtures and their activity has not been established. According to in vivo experiments, it is advisable to use mixture No. 3 to normalize glucose levels, and mixture No. 4 to normalize glucose and cholesterol levels.